Magnetic hard disk drives are useful devices for storing significant amounts of data and quickly accessing that data. Data is read from a hard disk by an electro-magnetic process in which magnetic domains resident in the disk are converted into electrical signals by a magnetic head or transducer positioned above the surface of a disk as the disk rapidly rotates about an axis. Similarly, data is written to a disk by the same or a different head or transducer which converts electrical signals into a magnetic field which magnetizes discrete locations of the data layer of the magnetic disk. Generally speaking, reversing the direction of the magnetic field produced by the transducer reverses the polarity of the magnetic domain of the disk.
In a conventional hard disk drive, the transducer or transducers for reading and writing data are positioned at the rear end of a slider which either rides in contact with the surface of the disk or flies above, but in close proximity to, the surface of the disk. The slider is connected to a load beam which, in turn, is connected to an actuator arm. The actuator arm pivots about a shaft under the influence of a voice coil motor in order to position the transducer, or read/write element, relative to the tracks of data resident on the disk. The local beam typically biases the transducer to a position in contact with the surface of the disk when the disk drive is turned off.
Transducers are delicate structures and are susceptible to corrosion. As a result, during the assembly process, a protective overcoat is applied to heads and sliders. The overcoat protects the slider from corrosion before final assembly while the head is exposed to the atmosphere. When assembly is completed, the actuator assemblies and disks are contained in a sealed housing which reduces or substantially eliminates the likelihood of corrosion of the transducers. Various filter elements are contained in the disk housing to maintain the relative purity of that environment.
Once the drive is fully assembled, it is subjected to numerous tests for purposes of quality control, and perhaps calibration. As part of these procedures, the drive is started and stopped numerous times, causing the slider to slide across the disk surface and the protective overcoat to be worn away. With the overcoat removed from the transducer(s), read and write operations can also be tested. Assuming all tests are successful, the drive is packaged and sold.
In those instances when the drive fails one or more tests, the problems may be addressed by reworking or repairing the drive. The rework process requires access to the drive and may result in exposure of the drive components to the atmosphere or other corrosive elements. The disassembly and rework process may also expose the unprotected transducers or magnetic elements of the heads to corrosion from exposure to the atmosphere. If the exposure to corrosive environmental elements is not minimized, the expected life and future operation of the disk drive will likely be adversely affected to the chagrin of the customer and manufacturer.